1. Technical Field
The present invention relates to a linear motion hydrostatic bearing assembly and, more particularly, to a self-compensating linear motion hydrostatic bearing assembly including a bearing carriage having a self-lubricating tape bonded to bearing surfaces of the carriage, and compensators formed in the bearing tape.
2. Background of Related Art
Linear motion hydrostatic bearings are well known and have been used for many years for the near frictionless movement of masses. Hydrostatic bearings are characterized as having excellent low friction, accuracy, and repeatability characteristics, with a theoretically infinite life. Hydrostatic bearings also have excellent damping characteristics which result from hydrostatic fluid acting as a shock absorber between the apparatus to which the bearing is associated and an applied load.
Typically, hydrostatic bearings maintain the distance between a bearing race and a support rail by supplying a thin pressurized film of fluid into the gap between the bearing race and the support rail. One type of hydrostatic bearing is a self-compensating hydrostatic bearing. Self-compensating hydrostatic bearings respond automatically to a change in bearing gap by changing the flow of fluid to pockets positioned along the bearing races.
Generally, self-compensating hydrostatic bearings have compensators formed on the internal surfaces of the bearing. Each compensator includes a collector, a supply groove, and a pocket consisting of a relief extending longitudinally along the length of a bearing carriage. Several processing techniques are currently used to form the compensators including injection molding and die casting on a collapsible core, electro-discharge machining and conventional machining. However, these techniques are complex, time consuming and expensive.
Additionally, self-compensating hydrostatic bearings have races subject to wear or damage upon the advent of a loss of hydrostatic fluid pressure. Since upon the loss of hydrostatic fluid pressure, a bearing carriage is no longer supported on a film of fluid above a support rail, galling and other damage to the being race may occur.
Accordingly, a need exists for an improved self-compensating hydrostatic bearing which can be manufactured without the costs and complexity associated with conventional techniques. Further, a need also exists for an improved self-compensating hydrostatic bearing with the ability to de-sensitize the effects of a loss of hydrostatic pressure.